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UNIVERSITY  OF-  Ar^lZON/C\. 

SCHOOL  OF  MINES 

Theo.  B,  Comstock.  Director. 


BULLETIN  No.  a 


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The  Testing  Laboratories,  with  Schedule  of  Rates 

treatment, OF  ORES. 


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TUCSON,  ARIZONA, 

APRIL  1,  1892. 

Daily  Citizen  Print,  Tucson. 


FACULTY,  ETC. 

THEODOf^E  Bf^Y/}NT  COMSIOCK,  So.  D.,  Director. 
Professor  of  Mining  and  Metaiiurgy, 

B.  Agr.,  Penn’a  State  Coll.,  1868;  B.  S.,  Cornell,  1870;  Sc.  D.,  Cornell, 
1886.  -  Instructor  in  Botany,  Cornell,  1869-70;  Ist  Ass’t  Geologist,  Morgan 
Expedition  to  Brazil,  1870;  Professor  of  Nat’l  Science,  Pelham  Priory,  N. 
Y.,  1872-  73;  Lecturer  on  Natural  Science,  N.  Y.  nnd  Cincinnati,  1873:  Geo¬ 
logist,  Capt.  Jones’  N.W.  Wyoming  (including  Yellowstone  Park)  Expedition, 
1873;  Director,  Kirtland  Summer  School  of  Natural  History,  Cleveland,  O., 
1875;  Acting  Professor  of  Geology  and  Paleontolog}\  Cornell  University, 
1875-79;  Manager  of  Mines  and  Mill,  Silverton  and  Eureka,  Colorado, 
1879-85;  Professor  of  Mining  Engineering  and  Physics,  University  of  Il¬ 
linois,  1885—89;  Assistant  State  Geologist  of  Arkansas,  1887  and  1888; 
Geologist  for  Central  Texas,  State  Geological  Survey,  1889—91.  Member 
American  Institute  Mining  Engineers;  Fellow  Geological  Society  of  Amer¬ 
ica;  Fellow  American  Assoc  Adv.  Sci;  Councillor  American  Institute  of 
Civics. 

CM/iRLES  BRRNRRD  GOLLiNGWOOD,  M.  S., 

Professor  of  Chemistry. 

B.  S.,  Agricultural  College,  Michigan.  I885,  M.  S.,  1890;  Adjunct  Pro¬ 
fessor  of  Chemistry,  University  of  Arkansas,  1888— 90;  Chemist,  Arizona  Agri¬ 
cultural  Exper.  Sta.  and  Professor  of  Chemistry,  Univ.  of  Arizona,  1890  to 
present. 

l/RSR  EDWiN  STOLBRRND,  C.  E., 

Professor  of  Matherr,atios. 

Chief  draughtsman,  etc.,  with  Madeira  and  Mamore  R.  R.,  Brazil.  1878—79; 
2nd  Lieut.,  13th  U.  S.  Infantry,  1879—85;  Field  Engineer  Officer,  1881—82; 
Professor  of  Mathematics,  Engineering  etc..  State  Agricultural  College  of 
Colorado,  1885-91;  Engineer-in-chief,  Larimer  and  Weld  County  Reservoir 
and  (  ity  Engineer,  Ft.  Collins,  Colorado,  1885—91.  Meteorologist  and  Ir¬ 
rigation  Engineer,  Arizona  Agricultural  Experiment  Station  and  Professor 
of  Irrigation  Engineering,  School  of  Agriculture,  Univ.  of  Arizona,  1891  to 
present. 


Professor  of  Geoiogy  and  Mineralogy. 

* 

Professor  of  Physics  and  iPppiied  Mathjematics- 

* 

Professor  of  li/jechanics  and  Industrial  Drauuing. 

* 

instructor  of  Assaying. 

P.  S.  STOCKTON,  Stenographer. 

P.  J.  FERGUSON ,  Engineer. 

*  Chair  to  be  tilled  whea  the  needs  of  the  Seliool  of  Mines  re.-iuire  such  appointment. 


UNIVERSITY  OF  ARIZONA* 


SCHOOL  OF  MINES. 

Tt^eo.  B.  Corrstock,  Director. 


BULLETIN  No.  2. 


The  Testing  Laboratories,  with  Schedule  of  Rates  for  the 

TREATMENT  OF  ORES. 


TUCSON  ,  ARIZONA 
APRIL  1  ,  1892. 


N.  B.  Bulletin  No.  1  of  the  Arizona  School  of  Mines,  issued  October  1, 
1891,  contains  a  statement  of  the  aims  and  objects  of  the  School,  with  the 
plans  adopted  to  carry  out  these  purposes,  and  explains  how  persons  in  any 
way  interested  in  these  matters  may  utilize  the  facilites  offered  and  aid  in 
extending  such  advantages. 

Future  Bulletins  will  discuss  practical  problems  of  interest  to  miners 
and  metallurgists,  and  give  some  of  the  results  of  actual  working  tests 
made  in  the  laboratories  of  the  School  of  Mines,  under  the  direction  of  com 
petent  men.  Kindly  write  to  the  Director  if  you  are  helped  by  any  sug_ 
gestions,  and  give  us  an  account  of  such  difficulties  as  you  may  meet  in  the 
mining  or  after-treatment- of  ores.  Remember,  if  we  do  not  come  close  to 
your  needs,  it  is  our  purpose  to  have  it  your  fault,  not  ours. 

The  Trustees  and  Director  desire  to  express  satisfaction  with  the  generous 
words  of  approval  bestowed  by  the  people  of  the  Territory  upon  their  efforts, 
and  to  assure  all  that  no  pains  will  be  spared  to  make  the  testing  laboratories 
particularly  adaptable  to  the  needs  of  Territorial  industries. 

Attention  to  the  SCHEDULE  OF  RATES  announced  in  this  Bulletin, 
on  page  9,  will  avoid  unnecessary  correspondence. 

This  and  succeeding  numbers  of  the  Bulletin  will  be  sent  to  those  who 
request  to  have  their  names  placed  upon  the  mailing  list. 


ARIZONA  SCHOOL  OF  MINES. 


THEO.  B  COMSTOCK,  D  IRECTOR. 


Wo.  3. 


synopsis: 

Practical,  Advantages  of  the  School  of  Mines  to  Miners  and  others. — 

Results  op  Correspondence  with  those  using  the  facilities  offered  in 
Bulletin  No.  1.— I.  Requests  for  Information,  Etc.— II.  Prelimin¬ 
ary  Tests  of  ores  and  minerals. — III.  Working  Tests  of  Ores. — 
1,  Assaying;  2,  Sampling;  3,  Concentrating;  4,  Reducing;  5,  Ex¬ 
perimenting;  6,  Miscellaneous. 

Schedule  op  Rates. 

E.^tension  of  Inbtuction  by  popular  lectures  upon  practical  subjects. 


Uacililies  ©fferedle  ^zc. 

'rhis  second  issue  of  the  Bulletin  is  the  direct  result  of  such  ex-, 
perience  as  has  been  gained  in  the  last  three  months  regarding  the  ac¬ 
tual  situation,  as  it  affects  the  growth  and  development  of  the  School 
of  Mines. 

The  building  up  of  a  great  University  in  any  given  locality  presup¬ 
poses  needs  and  conditions  which,  for  the  best  success,  involve  almost 
universal  demands,  inclusive  of  very  extensive  pecuniary  resources. 
The  combined  bounty  of  the  U.  S,  and  Territorial  Legislatures  has  pro¬ 
vided  funds  which  are  liberal  enough  for  a  certain  limited  application, 
but  which  would  only  be  frittered  away,  if  extended  over  too  wide  a 
rai-ge. 

It  has,  therefore,  been  wisely  determined  by  the  Board  of  Regents 
and  University  Council,  after  much  careful  consideration,  that,  without 
disregarding  the  proper  facilities  for  general  culture,  the  province  of  a 
College  in  the  University  of  Arizona  must  for  the  present  be  very  large¬ 
ly  the  fostering  and  developing  of  the  material  resources  of  the  Terri¬ 
tory,  and  the  training  of  men  and  women  fitted  to  practically  cope  with 
the  special  problems  which  demand  solution  at  our  own  doors. 


o  "l 


4 


In  pursuance  of  this  policy  in  its  application  to  the  School,  or  College, 
of  Mines,  a  general  plan  has  been  devised  and  an  equipment  of  apparatus 
provided  with  reference  to  the  actually  existing  needs  as  these  have  been 
made  manifest  in  a  careful  scrutiny  of  the  field.  At  the  same  time  a  very 
considerable  reserve  of  money  and  of  adaptable  space  has  been  held  for 
application  to  new  wants,  as  they  may  become  apparent  from  time  to 
time. 

While  we  are  meeting  all  demands  for  instruction  within  the  scope 
of  our  organization,  the  principle  is  fully  recognized  that  brains  are  of 
more  importance  than  buildings  and  apparatus  without  them.  It  is  our 
purpose  to  secure  the  best  possible  talent  for  every  department,  that  no 
uncertain  work  may  be  done,  and  that  all  tests  and  reports  may  be  con¬ 
fidently  relied  upon  by  those  who  may  have  occasion  to  use  the  facilities 
afforded  here. 

For  these  reasons,  although  a  Faculty  will  be  gradually  formed  as 
necessity  requires,  there  have  been  few  appointments  as  yet.  At  the 
same  time  negotiations  still  pending  will  assure  the  selection  of  thorough¬ 
ly  competent  men  whenever  their  services  may  be  needed. 

'Fhe  Metallurgic  Annex  and  the  Assay  Laboratories  have  been 
largely  equipped  since  the  publication  of  the  last  Bulletin,  and  not  a 
few  tests  have  already  been  made  of  ores  and  minerals  from  different 
parts  of  the  I'erriiory.  'Fhe  mill  is  now  partly  in  running  order  and  we 
are  prepared  to  make  working  tests  by  the  processes  most  suitable  for 
Aiizmaores,  The  large  correspondence  which  has  arisen  with  refer¬ 
ence  to  this  branch  of  our  work  shows  clearly  the  need  of  the  facilities 
provided  and  the  wisdom  of  this  appropriation  of  funds  by  the  Board  of 
Regents.  Heretofore  the  Director  has  been  overwhelmed  with  appli- 
•cations  of  this  character,  vvhich  have  at  times  been  but  dilatorily  re¬ 
ported  upon,  owing  to  insufficient  preparation  for  the  work  and  lack  of 
proper  assistance.  But  is  is  gratifying  to  find  such  demands,  and  it  will 
not  be  long  ere  we  shall  be  fully  prepared  to  meet  them  promptly. 

As  illustrations  of  the  scope  and  objects  of  this  branch  of  our  work, 
a  general  review  ol  the  correspondence  of  the  past  three  months  is  here 
given.  A  classification  of  this  niakes  five  natural  divisions,  as  follows: 

I.  Requests  for  Information  Regarding  the  Resources  of  Arizona. 

Letters  of  inquiry  are  constantly  being  received  from  all  parts 
of  the  United  States,  from  manufacturers,  collectors,  museums,  and 
other  sources.  'Fhese  embrace  a  wide  variety  of  requests  from  general 
to  specific.  Among  those  recently  received  may  be  instanced  com¬ 
munications  from  orhcers  of  the  World’s  Fair  Commission;  prominent 
officials  connected  with  national  and  state  survevs;  authorities  upon  gems 
and  precious  stones;  parties  desiring  collections  or  special  varieties  of 
Arizona  minerals;  manufacturers  and  others  seeking  commercial  min¬ 
eral  products;  persons  asking  information  about  mines  in  the  Territory, 
and  many  other  related  queries. 


5 


Upon  the  subject  of  meteorites  there  has  been  the  most  correspond¬ 
ence,  but  considerable  interest  has  been  manifested  in  the  matter  of 
onyx,  which  is  an  important  product  of  the  Territory.  Requests  have 
also  come  for  information  concerning  possible  supplies  of  coal,  magnesia, 
asphaltum,  corundum  and  other  minerals. 

It  is  the  desire  of  the  Director  of  the  School  of  Mines  to  obtain  all 
possible  information  upon  these  subjects  and  to  extend  a  knowledge  of 
them  in  such  manner  as  to  best  subserve  the  interests  of  the  general 
public.  The  formation  of  a  complete  collection  of  the  minerals  of  Ariz¬ 
ona  has  been  begun  and  donations  are  respectfully  solicited.  A  few 
specimens  have  already  been  kindly  sent  in  by  friends,  for  which  thanks 
are  due  the  donors. 

II.  Preliminary  Tests  Of  Ores  and  Minerals. 

Applications  classed  under  this  head  began  to  come  in  late 
in  November,  but  few  had  been  received  before  January  of  this  year. 
Delays  in  the  receipt  of  apparatus  and  the  time  necessarily  consumed  in 
fitting  up  the  laboratories,  have  prevented  any  efforts  to  increase  appli¬ 
cations  in  this  direction  until  now.  Notwithstanding  this,  however,  some 
sixty  lots  of  ore,  from  hand  specimens  to  a  number  of  pounds  in  each 
lot,  have  been  received  and  tested  by  such  simple  methods  as  can  be 
readily  applied  without  undue  consumption  of  time  and  materials. 

It  is  proper  to  state  here  that  the  object  of  this  work  and  the  reason 
for  performing  it  without  charge,  are  based  upon  the  belief  that  the  re¬ 
sults  to  the  industries  of  Arizona  will  be  more  than  commensurate  with 
the  cost,  d'here  is  no  intention  of  competing  with  local  assayers,  and 
any  work  offered  in  this  department  which  would  so  conflict  is  respect¬ 
fully  declined. 

The  class  of  work  which  will  be  put  into  this  category,  it  must  be 
distinctly  understood,  is  wholly  qualitative,  and  not  quantitative,  That 
is  to  say,  anyone  may  send  specimens  and  small  lots  of  ores  or  minerals 
for  simple  determination.  These  must  be  delivered  free  of  charge,  ac¬ 
companied  by  letter  stating  what  examinatiou  is  desired,  with  stamps 
inclosed  for  reply.  As  soon  as  convenient,  each  in  order  of  receipt,  a 
test  will  be  made  and  report  sent.  This  gratuitous  test  may  include  any 
or  all  of  the  following  determinations,  viz: 

T.  Name  and  character  of  the  mineral. 

2.  Presence  or  absence  of  gold,  silver,  copper,  or  other  valuable 
ingredient,  but  not  the  amount  of  any  metal. 

No  responsibility  is  assumed  for  anything  beyond  the  report  upon 
the  specimens  received.  Any  responsibility  for  the  authenticity  of  the 
discovery,  its  locality,  quantity,  or  the  like,  rests  wholly  outside  of  us. 
It  is  not  necessary  that  any  information  upon  these  subjects  be  given, 
although  such  will  be  welcome  as  a  guide  to  future  explorations  under 
the  auspices  of  the  School  of  Mines, 


The  minerals  already  examined  have  come  from  various  parts  of 
Arizona  and  this  work  has  brought  the  School  of  Mines  directly  into  har¬ 
monious  relations  with  numerous  miners,  prospectors  and  others  who 
have  much  needed  this  means  of  determining  to  a  certainity  whether 
they  are  developing  prospectively  valuable  deposits. 

It  is  too  early  to  draw  definite  conclusions  from  such  examinations, 
but  it  may  be  said  that  the  general  results  indicate  the  probable  ex¬ 
istence  of  gold  in  Arizona  in  larger  quantity  and  over  wider  areas  than 
has  previously  been  recognized.  And  it  is  reasonably  safe  to  assert,  not 
alone  from  these  premises,  that  the  ordinary  mode  of  occurence  of  the 
gold  is  not  what  has  been  the  assumption  of  some  who  have  introduced 
plants  for  its  reduction.  This  discovery  has  influenced  somewhat  the 
selection  of  machinery  for  our  experimental  plant;  and,  if  further  study 
confirm  this  hint,  it  will  eventually  have  a  most  important  bearing  upon 
the  practical  working  of  our  auriferous  ores. 

The  existence  of  manganese  ores  has  also  been  proven  by  these  tests. 
These  may  become  of  value  in  the  process  best  adapted  for  a 
large  class  of  our  local  ores.  Important  ores  of  iron  have  come  to  our 
knowledge  through  the  specimens  tested,  A  possibly  valuable  deposit 
of  a  refractory  material  allied  to  soapstone  has  been  made  apparent  re¬ 
cently  by  the  same  means. 

III.  Working  Tests  of  Ores. 

Until  now  we  have  not  been  ready  to  announce  the  terms  upon 
which  ores  may  be  tested  upon  a  working  scale;  but  a  few  lots  have  been 
sent  by  residents  of  Arizona  and  elsewhere.  These  have  been  promptly 
treated  when  possible,  in  small  lots,  and  others  have  been  held  until  the 
machinery  was  in  position  for  manipulation.  This  branch  of  our  work 
is  necessarily  divided,  as  the  objects  are  not  always  the  same.  In  the 
Schedule  on  page  the  charges  for  tests  are  given  with  as  much  de¬ 
tail  as  possible,  but  individual  cases  must  usually  be  separately  consid¬ 
ered.  It  may  be  stated  as  a  guiding  principle  that  we  solicit  mainly 
such  work  as  may  be  of  most  general  benefit  and  that  we  will  not  com¬ 
pete  with  assayers  or  mill-owners  in  the  field  covered  by  them.  All 
work  which  can  as  well  be  done  by  regular  custom  mills  or  assayers  will 
only  be  undertaken  by  the  School  cf  Mines  at  prices  much  above  the 
standard  rates. 

To  afford  some  basis  for  computation,  the  work  of  this  class  may 
be  divided  into  six  categories,  as  follows; 

1.  Assaying. 

2,  Sampling. 

3  ('oncentrating. 

4.  Reducing. 

5.  Experimenting. 

6.  Miscellaneous. 


I  Assaying. 

Requests  for  assays  of  specimens  have  been  numerous.  It  is 
not  just  nor  feasible  for  the  School  of  Mines  to  engage  in  this  work  to 
the  detriment  of  those  who  earn  a  living  thereby,  and  it  is  difficult  to  see 
what  advantage  will  accrue  to  anyone  by  such  procedure.  We  have, 
therefore,  purposely  placed  the  rates  for  such  services  much  above  the 
usual  charges  outside.  Where,  for  any  reason,  our  certificate  may  be 
desired,  assays  at  these  advanced  rates  will  not  be  declined.  Umpire 
assays  now  made  in  San  Francisco  or  Denver  can  as  well  be  done  at 
home,  and  the  revenue  obtained  from  this  source  will  be  all  expended  in 
extending  facilities  for  the  benefit  of  the  mining  industry.  It  is 
earnestly  requested  that  large  samples  be  sent,  as  it  is  cesired  to  make 
duplicate  assays  and  to  preserve  a  part  of  the  pulp  for  a  reasonable  time. 
A  detailed  record  of  all  assays  will  be  kept,  from  which  duplicate  cer¬ 
tificates  may  be  obtained  only  upon  the  order  of  the  consignor  or  his 
legal  representatives  or  successors. 

2.  Sampling. 

The  sampling  of  ores  delivered  to  the  works  will  include  all 
work  required  to  obtain  an  average  pulp  sample  of  each  lot  of  more 
than  five  (5)  pounds,  with  a  certificate  of  assay  of  the  same.  The  larger 
the  lot  furnished  the  greater  will  be  the  value  of  deductions  based  upon 
such  samples.  In  no  case  can  any  responsibility  be  assumed  for  anything 
beyond  what  appears  in  the  certificate  furnished  by  the  Director  of  the 
School  of  Mines.  The  essentiai  samp/ ing  of  ores  other  wise  treat¬ 
ed  is  included  in  the  charges  made  for  such  treatments 

3.  Concentrating. 

In  all  cases  of  tests  of  the  adaptability  of  ores  to  wet  or  dry 
concentration,  it  will  be  desirable  to  send  one  or  more  sacks  of  the  aver¬ 
age  product  for  pieliminary  examination.  This  will  avoid  further  ex¬ 
pense  if  the  result  is  unfavorable  and,  in  some  cases,  it  may  answer 
every  useful  purpose.  But,  for  accurate  results,  it  will  often  be  neces¬ 
sary  to  ship  a  ton,  or  more  in  some  cases.  The  concentration  test  will  or¬ 
dinarily  comprise  sampling  and  assaying  of  the  original  ore  and  of  the 
total  product.  A  report  in  detail  including  assays  of  headings,  tail 
ings,  and  all  jig  products  may  be  obtained  at  a  reasonable  additional 
cost. 

4.  Reducing. 

The  selection  of  the  best  mode  of  working  will  usually 
be  most  economically  left  to  us,  but  some  calls  have 
been  made  for  the  reduction  of  small  lots  by  particular 
processes,  as  amalgamation,  chlorination,  lixiviation,  or  other 
mode  of  treatment.  Such  tests  will  usually  involve  the  determination  of 
the  percentage  of  loss  in  the  treatment,  thus  requiring  several  assays  for 
each  lot.  All  necessary  investigations  of  this  nature  are  included  in  the 


8 


schedule  rate.  The  quantities  required  for  testing  by  any  particular 
process  will  be  made  known  upon  application. 

5.  Experimenting. 

This  class  of  work  comprises  such  tests  as  may  be  required  to 
determine  the  mode  of  treatment  best  adapted  to  given  ores.  The 
charge  for  such  investigations  will  vary  with  the  material  to  be  examined, 
but  it  will  usually  be  equivalent  to  the  sum  of  the  charges  for  each  indi¬ 
vidual  test  required,  less  a  liberal  discount,  A  hypothetical  case  will 
best  illustrate  this: 

Given  an  ore  which  is  found  not  to  amalgamate  readily,  and  which 
does  not  yield  good  results  by  chlorination,  nor  by  lixiviation,  but  for 
which  a  special  process  of  electrolysis  may  be  devised  after  much  exper¬ 
imentation.  The  charge  for  all  this  work  would  not  be  as  much  as  the 
sum  of  all  the  tests,  as  one  result  would  commonly  furnish  clues  to 
the  cause  of  success  or  failure  of  another  method.  The  case  selected  is 
extreme  for  these  reasons,  and  one  not  very  liable  to  occur.  The  usual 
mode  of  procedure  with  unknown  ores  would  be  a  careful  chemical  an¬ 
alysis  as  a  first  step,  and  this  alone  would  in  most  cases  determine  the 
kind  of  treatment  best  adapted  to  the  ore. 

Work  of  this  character  must  necessarily  be  the  subject  of  negotia¬ 
tion  beforehand,  but  as  it  does  not  compete  with  established  industries 
in  any  sense,  the  charges  will  always  be  moderate.  In  very  many  ins¬ 
tances  mere  inspection  of  the  ore  will  enable  a  judgment  to  be  formed 
as  to  the  most  suitable  process  of  reduction, 

6.  Miscellaneous. 

Many  questions  are  constantly  arising  m  the  development  of 
mines  and  working  of  ores.  Such  of  these  as  are  of  general  interest  will 
be  answered  as  far  as  possible  in  future  issues  of  the  Bulletin,  and  some 
of  those  which  appear  to  be  highly  important  may  be  investigated  for  the 
benefit  of  the  mining  industry.  At  times  it  may  happen  that  ores  of 
particular  kinds  will  be  needed  for  use  in  instruction,  in  which  csL'.e 
work  of  benefit  to  the  owner  may  be  done  in  return  for  the  donation  of 
the  ore,  even  if  it  be  not  profitable  to  work. 

The  subjects  which  are  being  especially  studied  at  this  time  are  the 
treatment  of  the  sulphide  gold  bearing  ores  of  Arizona,  and  the  forma¬ 
tion  of  mineral  veins,  as  an  exj^erimental  investigation 

Any  person  who  has  doubts  or  difficulties  is  cordially  invited  to 
make  them  known,  and  in  some  w^ay  or  another  an  effort  will  be  made 
to  dispel  them  to  the  best  of  our  ability, 

V.  Extension  of  the  Work  of  Instruction. 

There  has  been  expressed  in  various  quarters  a  desire  to  utilize  the 
facilities  for  instruction  in  ways  outside  of  the  regular  University  train¬ 
ing,  as  announced  in  Bulletin  No.  i  of  the  School  of  Mines  This  de¬ 
mand  has  come  from  those  whose  business  pursuits  will  not  allow  them 
to  attend  day  classes  or  to  take  the  work  of  special  students. 


The  Board  of  Regents  and  the  Director  of  the  School  of  Mines  are 
anxious  to  meet  this  need,  if  it  be  a  real  one,  and  to  this  end  an  earnest 
request  is  now  made  that  all  who  are  interested  will  express  their  wishes 
freely.  The  exact  method  of  supplying  such  a  want  can  best  be  deter¬ 
mined  later,  but  it  seems  probable  that  it  may  take  the  form  of  evening 
lectures  and  demonstrations  at  the  University  and,  if  advisable,  occasion¬ 
ally  in  the  various  mining  centers  of  Aiizona, 

It  will  not  be  feasible  to  begin  this  work  unless  a  reasonable  number 
of  bonafide  applications  are  registered.  Any  persons  who  may  desire  to 
avail  themselves  of  an  opportunity  of  this  character  are  invited  to  corres¬ 
pond  with  the  Director.  Fees,  it  any.  will  be  only  nominal. 


SCHEDULE  OF  RATES. 


Preliminary  or  specimen  tests  (qualitative): 

Assaying. 


FREE. 


Silver . $  2.50 

Gold  and  silver .  3.50 

Lead .  2.50 

Copper .  3.00 


Zinc,  tin,  arsenic,  antimony,  bismuth,  nickel,  cobalt,  etc.,  each,  5.00 

Sampling, 


Lots  of  100  pounds  or  less,  including  assays  of  three  metals .  5.00 

Each  additional  100  pounds,  to  500  pounds .  1.00 

Over  500  pounds,  to  1  ton, .  10.00 

Each  additional  ton . .  4.00 


REDUCING  TO  METAL  BY  ANY  PROCESS,  AS  BELOW: 

A.  Simple  determination  of  minimum  loss  by  treatment  of  small 
pulp  sample;  same  as  sampling  charge  for  same  weight.  (See  above.) 

B.  Treatment  of  entire  lot:  sampling  charges,  plus  charges  for  extra 
assays  required,  plus  cost  of  labor  and  of  materials  consumed,  plus  25 
cents  per  hour  for  use  of  each  apparatus  employed;  subject  to  discount 
in  proportion  to  amount  of  work. 

Amalgamation,  including  crushing,  etc.,  with  full  report. 


would  thus  cost  for  first  ton  treated . S20.00 

Two  tons .  25.00 

Large  lots,  proportionately  less,  per  ton;  small  lots  more  in  proportion. 
0:her  processes  according  to  time,  labor  and  material. 

CONCENTRATING  (Including  all  Assays.) 

•Wet  or  dry  test  of  small  lot  (under  500  pounds) . $15.00 

500  pounds  to  I  ton .  20.00 

Each  additional  ton . ' '  ‘ ' .  7.00 


Experimental  tests  and  other  work,  at  rates  to  be  agreed  upon  in 
each  instance. 


Directions  for  Shipping  Ores. 

The  following  letter  explains  itself,  and  all  consignors  of  ore  in  A  rizona 
may  avail  themselves  of  this  reduced  rate  of  freight,  via.  the  S.  P.  R.  R. 

San  Francisco,  Cal.,  April  6,  1892. 

Mr.  Theo.  B.  Comstoc®', 

'Director  of  School  of  Mines, 

University  of  Arizona. 

Dear  Sir:  Replying  to  your  favor  of  15th  inst ,  preferring  request  for 
special  rates  of  freight  on  ores  for  your  Test  Laboratory. 

We  believe  with  you  that  good  results  to  the  Territory  will  flow  from 
your  work,  and  for  this  reason  take  pleasure  in  informing  you  that  we  will 
carry  ores  in  lots  of  not  more  than  one  ton,  from  any  point  in  Arizona  to 
Tucson,  at  the  following  nominal  rates: 

For  50  miles  or  less . SI. 00  per  ton. 

For  distance  over  50  miles . 2  cents  per  ton  per  mile. 

Minimum  charge  for  small  shipments  . .  25  cents. 

W e  do  not  feel  that  we  can  aflbrd  to  carry  larger  quantities  than  one 
ton  at  these  rates. 

To  get  the  benefit  of  this  concession,  shipments  must  be  consigned  to 
‘•Director  of  the  School  of  Mines.”  As  this  is  only  an  experiment,  we  will 
limit  the  application  of  these  rates  to  six  months  from  date. 

Trusting  that  this  will  be  entirely  satisfactory  to  you,  I  remain. 

Yours  Truly, 

C.  F.  Smurr,  General  Freight  Agent. 

The  Director  proposes  to  visit  every  mining  camp  in  Arizona  within  a 
few  months,  to  familiarize  himself  with  the  situation  and  to  study  the  needs 
of  the  industry  in  matters  where  the  School  of  Mines  can  properly  offer 
co-operation  and  assistance.  Arrangements  are  being  made  for  the 
preliminary  survey  of  the  geology  of  the  Territory  preparatory  to  more  com¬ 
plete  work  hereafter. 

Address  all  communications  to 

THEO.  B.  COMSTOCK, 
Director  of  the  School  of  Mines, 

Tucson,  Arizona. 

UNIVERSITY  OF  ARIZONA, 

April  1,  1892. 

Board  of  Regents:  M.  P.  Freeman,  Chancellor;  J.  M.  Ormsby,  Sec¬ 
retary';  S.  M.  Franklin,  John  Gardner. 


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